1. Field of the Invention
The present invention relates to a tongue for a seat belt device that structures a seat belt device of a vehicle, and to a seat belt device that is equipped with this tongue.
2. Related Art
At a tongue for a seat belt device that is disclosed in Japanese Patent Application National Publication No. 2009-525909 (Patent Document 1) (this tongue is called the “belt tongue portion” in Patent Document 1), the main body portion thereof (called the “tongue portion main body portion” in Patent Document 1) is curved around an axis whose axial direction is the width direction of a webbing (called “belt webbing” in Patent Document 1), and a curved, plate-shaped bending-and-fastening element is provided at the inner side of this main body portion.
When, due to the vehicle rapidly decelerating, the body of the vehicle occupant pushes the webbing forward, and, due thereto, the tension of the webbing increases, the bending-and-fastening element slides along the inner side of the main body portion of the tongue due to this tension. The bending-and-fastening element that slides in this way pushes the webbing from a thickness direction one side thereof, and, due thereto, the bending-and-fastening element, together with an upper bar of the main body portion at the tongue, clamps the webbing. Due to the webbing being clamped in this way, the portion of the webbing, which portion is further toward the proximal end side than the tongue, moving further toward the distal end side than the tongue is suppressed.
However, when tension is applied to the webbing in the state in which the webbing is clamped, localized load is applied to the clamped portion at the webbing. Therefore, the webbing must be endowed in advance with strength that is able to withstand such load.